Fuel injection system



Nov, 28,

1961 F. w. HAMlLToN FUEL INJECTION SYSTEM Filed Aug. 29, 1958 4. mmm

NWWN

OR. f7/cvs' 14./ #477127571 lNvENT United States Patent G 3,e10,442 FUEL INJECTION SYSTEM Francis W. Hamilton, Detroit, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Filed Aug. 29, 1958, Ser. No. '757,952 11 Claims. (Cl. 12S- 119) This invention relates to a fuel injection system of the type disclosed in the related copending application of Thomas M. Ball et al. Serial No. 751,999 iiled luly 30, 1958 and assigned to applicants assignee, and in particular relates to a Vcold start enrichment device for use therein.

In fuel injection systems as in other fuel systems for use on internal combustion engines, there is a need to provide some means to supplement the fuel supply to the engine under cold starting conditions which means automatically reduces its fuel supplements as the engine warms up. This additional fuel supply is necessitated for starting cold internal combustion engines due to the low vapor pressure developed by gasoline at cold engine temperatures. This low vapor pressure allows little fuel vaporization at low engine temperatures, and additional fuel is required in the combustion chamber to provide the amount of fuel vapor necessary to obtain the proper fuel-air mixture ratio for combustion.

In the fuel injection system herein presented, a bimetallic thermostatic member is connected to a shiftable fuel metering member of the fuel metering system and communicates with air that is continuously drawn through a conduit exposed to the gases Within an exhaust manifold of the engine. The thermostatic member has the property of expanding at cold engine temperatures to exert a force on the said member of the fuel metering system to increase the ow of fuel to the engine. The force exerted by the cold thermostatic member on the shiftable metering member in return flow metering systems will tend to restrict the return ow of fuel to the fuel supply and in direct inlet metering systems will tend to increase the size of the fuel inlet metering orice to enhance the ow of fuel to the engine.

An object of this invention is to provide a fuel injection system capable of delivering an enriched fuel-air mixture to a cold internal combustion engine.

Another object is to provide a device sensitive to exhaust manifold temperature for use on an internal combustion engine fuel metering system to give an additional fuel flow to said engine during cold starting conditions.

Another object is to provide a return flow fuel metering unit of a fuel injection system with a cold start enrichment device.

Another object'is to provide an internal combustion engine cold start enrichment device utilizing as a sensitizing medium air drawn through -a conduit and heated by the gases in an exhaust manifold.

Further objects and advantages will become apparent from the following specilication and drawings, in which:

FlGURE l represents a View partly in cross-section of the complete fuel injection system;

FIGURE 2 represents a view partly in cross section of a variation of the bimetallic thermostatic member of FIGURE 1; and

FIGURE 3 represents aview in tion of the cold start enrichment and 2. Y

In FIGURE 1 is shown a fuel injection metering system for an internal combustion engine 10, said engine having heads 12 and exhaust manifold banks 14 on each head thereof, said metering system comprising a fuel speed metering unit 16, a fuel load metering unit 18, an accelerator pump 20, and a fuel supply 22.

cross section of .a variadevices of FIGURES l The fuel speed in conduit 114 is provided to regulate the pressure transmetering unit 16 is provided with four housing portions 22, 24,k 26, and 28 separated from each other by diaphragms 30, 32, and 34respectively to provide chambers 36, 38, 40, and 42. Chamber 36 communicates with fuel supply 22 through conduit 44. A fuel pump 46 in said conduit supplies a constant volume of fuel through filter 48 to chamber 36 during the operation of said engine regardless of the engine load or speed. A return flow metering orifice 50 in said housing portion 22 connects chamber 36 With a return flow conduit 52 which communicates with the inlet check valve 54 off yaccelerator pump 30.

A return flow metering needle 56 having a tapered point 58 is secured to each of said diaphragms 30, 32, and 34 by suitable grommets 60.

A iiyweight support 62 pivotally supports ilyweights 64 and 66 and is secured to a flexible shaft 68 which is operatively connected to the ncgine 10 to rotate ata speed directly proportional to engine speed. Flyweights 64 and 66 have projections 70 and 72 respectively thereon which abut the end of needle 56 as said flyweights pivot outwardly in response to rotation 56 toward orifice 50 against the force applied in the opposite direction Aagainst diaphragm 30 by the fuel in chamber 36.

A conduit 74 connects chamber 36 to the upstream chamber 76 of the load sensor 18 which upstream chamber communicates with a downstream fuel distribution chamber 78 of the load sensor across a load metering orifice 80. A tapered load metering needle 82 having a tapered end 84 positioned in orifice 80 is opera-tively connected to piston 86 reciprocably mounted in cylinder 88, which cylinder operatively communicates Ywith the low pressure portions of each intake manifold 90 on said engine through conduit 92. Low pressure transmitted through conduit 92 will cause piston 86 to be drawn upwardly against the force of spring 94 to thereby urge the tapered end of needle 82 into closer proximity to the sides of orice and conversely high pressure in the intake manifolds will tend to urge needle 82 to a more open position with respect to oriiice 80. A plurality of nozzle feed conduits 96 extend from chamber 78 of the load sensor to an equal number of fuel injection nozzles 98 located upstream of the throttle valves 100 of the individual intake manifold sections 90. The atomizing air supply to the nozzles 98 isV obtained from pump 102 through intakes 104 and 106 and is transmitted to the branch air conduits 108 of said nozzles by a main air conduitA 110. Chamber 78 of the load sensor is connected to chamber 38 of the speed sensor by conduit 112 to provide an adjustment of the return flow metering needle 56 with respect to orifice 50 based on the `pressure Vdiierential existing across oriiice 80 of the load sensor.

An idle boost conduit 114 communicates with one of said manifold sections at a point adjacent the edge of the throttle valve of that section and with the chamber 40 of the speed sensor. An air bleed valve 116 mitted to chamber 40 fromsaid manifold `section during idling of the engine in order to regulate thereby the speed of the engine at idling.v Under normal idling conditions the pressure in chamber 40 is lower than in chamber 42 which is vented to the atmosphere and said pressure in chamber 42 tends to urge the needle 56 toward orifice 50 to retard the ow of return -fuel therethrough and provide a sufficient fuel supply for idling. The requirement of this additional boost to needle 56 is due to the fact that a slow engine speed the yweights are not nng outwardly. with sufficient-force to negate the frictional resistance of the needle S6 to movement. Y

The accelerator pump 20 having an inlet check valve 54 and an outlet check valve 118 receives fuel through of shaft 68 to urge needle 3 Y 4 said inlet valve into chamber 120 from which the return 78 of the load sensor. When the forces transmitted b5 fuel continues through the return ow conduit 52 back said ilyweights and the fuel in said chamber 38 once agair to the tank. The depression of the accelerator will force balance the force transmitted in the opposite direction by piston 122` of said pump 20 downwardly to force fuel the fuel in chamber 36, the ilow of fuel through orice through check valve i118 and through conduit 124 directly 5 80 will be substantially directly proportional to the speed to the downstream chamber 78 of the load sensor. of the engine and will correspond to the llow of air into Attached to portion 28 of the fuel speed metering unit the intake manifold. 16 is a cold start enrichment device designated generally Assuming that the elements of the fuel injection system as 126. A bimetallic thermostat coil 128 having its inner as shown are in their exact positions represented during end 130 secured against movement is mounted in housing 10 cold starting of the engine, member 56 which is normally 132. End 134 of the coil abuts a projection 136 which further removed from orifice 50 than is shown in the forms an end of booster shaft 138 slidably mounted in drawing has lbeen moved closer to orifice 50 by force supbushing 140. Shaft 138 abuts at its other end an arm 142 plied by the cold thermostat coil 128. As a result of which arm is pivotally mounted at 144 and abuts collar this new position of the metering member 56, the flow 146 on metering member 56. A piston 148 carries a con- 15 of return fuel through orice 50'is retarded and a fuel necting rod 150 which is connected to end 136 of shaft pressure increase over that during hot starting is felt in 138. Conduit -4 extends through exhaust manifold 14 chambers 36 and 76 which pressure increase results in and is heated by the exhaust gases therein. Groove 158 an increased pressure drop across orifice 80 which results in piston 148 and groove 160 in housing 132 provide in an increased fuel flow across orifice 80 into chamber cooperating bypass passages to limit the effect of low 78 and to the engine through conduits 96.A As coil 128 pressure in conduit 156 on piston 148 and to prevent said warms up due to the air in conduit 154 being warmed by 1 piston from pulling the thermostat coil far to the righ-t the exhaust gases in manifold 14, said coil will gradually and to an ineffective position during engine warm-up. contract to a position shown by the dotted line 135 at It is noted in this respect that the function of the piston Which POsiiOll 110 fOrCe is developed by Coil 128 t0 hOOsf is only to maintain the coil taut at all times and not to member 56 toward orifice 50 and said member returns noticeably diminish the boosting effect of the coil on to the position it occupies during hot engine starting. It

member 56. is noted that as coil 128 contracts, piston 148 will main- In the variation of FIGURE 2 a bimetallio thermostat tain it taut and will prevent loose motion of shaft 138. member 129 has one end 127 secured against movement Moreover spring 145 attached i0 arm 142 and Projecby projecting portions of housing 132 and has its other 30 tion 147 within housing portion 28 constantly urges arm end 133 abutting projection 136 This member 12,9 eX- 142 against shaft 138 and prevents loose motion of said pands in the same manner as does coil 128 to exert a arm fuel adjusting forge on member 133 A secondary function of piston 148 is that of an The operation of the fuel injection metering unit 10 additional accelerator fuel boost means since a sudden will be described in relation to a ychange in static engine Opening 0f throttle 100 Will Cause arl. increased Prsssire operating conditions, that is oonstant engine speed and in manifold portion 90 which pressure increase will be load. Under said lstatic operating conditions, the comtransmitted through conduit 156 to piston 14S and cause bined forces exerted by flyweights 64 and 66 and the fuel it to move to the left with respect to FIGURES l and 2 in chamber 38 is balanced by the force exerted by the of the drawing and exert a fuel boost force on member fuel in chamber 36 and the return ow metering member 40 56 JfhrOllgh linkage 138 and 142- 56 is maintained stationary at a distance away from orifice IH the VaratiOn Shown in FIGURE 3 member 138 slidso. In this static condition, the amount of fuel delivered ably extends through a Solenoid -162 and thrOush fac@ to the distributing chamber 78 is constant and is equal 164 of armature 166 and abuts a bimeta-llic thermostat to the constant amount of fuel being delivered to the element 168. Armature 166 is slidably contained in system 'by the pump less the constant amount of fuel 45 Cavity 170 0f housing 172, said Cavity having spaced being returned to the fuel tank through the return flow bearing projections 174 to allow armature l166 to slide conduit 52. If this static condition represents the engine easily. As in FIGURES 1 and 2 conduit 154 communiduring normal driving speed, the pressure in chamber 42v Cates with the thermostat element through suitable ports has no noticeable eect on the operation of the unit and 176, and conduit v156 connected to intake manifold conmay be disregarded. It is only during idling and very duit 90 provides a means for sucking a continuous supply low engine speeds that the pressure differential across of air past said element 168. diaphragm 34 becomes significant. 'Ihe solenoid 162 is electrically connected into the As the throttle valves 100 are moved toa more open starter circuit and is energized as long as the starter K position vby the depression of the engine accelerator, an switch i178 is closed. Return spring 180 abutting housing increase in manifold pressure is transmitted to the load 28 and projections 182 on member 138 performs equivasensor piston through conduit 92 and moves said piston lently to the spring 145 in FIGURE 1 in taking the slack down to thereby move the load metering needle 82 to a out of the thermostat member. more open position with respect to the load metering In the operation of the device of FIGURE 3, solenoid orifice 80. The pressure differential existing lacross said '162 when energized by closing of switch 178 for engine 'orifice is consequently decreased as more fuel is allowed 60 starting draws armature 166 to the left and compresses to flow into chamber 78. This decrease in pressure difelement 168 if the engine is cold and if the air drawn ferential 4causes the flow` through orifice 80 to deviate into cavity 170 through conduit 154 is cold. The comfrom the desirable ow which is substantially directly pressive force of element 168 will be transmitted to proportionalto engine speed. To correct this condition member 138 to urge metering member 56 to the left to and bring 'the'pressure differential Iacross said orifice up 65 provide a starting fuel pulse to the engine in addiiton to a value where the flow'of fuel therethrough is subto that provided by the cold expanded element 168. if stantially directly proportional to engine speed, the fuel the engine is Warm when the starting switch is closed and pressure in fuel supply pressure chamber 36 and load the air drawn into cavity l17() is Warm, element 168 will sensor upstream chamber 76 communicating therewith be already in a compressed condition as shown by the is increased. This increase in pressure is accomplished dotted line 169 in FIGURE 3 and movement of arma- Vy moving the return flow metering member 56 closer ture 166 to the left will not cause element 1168 to exert 'to orifice 50 by the increased force transmitted by the a fuel boosting force on member 138. Independently of flyweights 64 and 66 as the engine speed is increased solenoid 162, element 168 operates in an equivalent and by the increased pressure in chamber 38 Vcaused by manner to the thermostat elements of FIGURES 1 and theincreased flow of fuel into the downstream chamber 2 by slowly decreasing the fuel boosting force on member 13S as the temperature of the exhaust gases in manifold 14 increases.

l claim:

l. In a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply conduit system, return flow fuel metering means in said conduit system, speed responsive means operatively connected with said metering means and adapted to be connected to said engine to regulate the flow of fuel thereto according to engine speed, and thermostatically operated means operatively connected to said fuel metering means and communicating with said exhaust manifold and responsive to changes in temperature of the gases Within said manifold to adjust said fuel metering means to supply additional fuel to the engine under cold starting and warm up conditions.

2. A fuel injection system for an internal combustion engine comprising a fuel supply, a fuel speed metering unit having a pressure chamber communicating with said fuel supply through a fuel feed conduit and also communicating with said fuel supply through a return flow metering orice in said fuel supply pressure chamber, a fuel load metering unit having an upstream chamber and a downstream chamber and a load metering orifice connecting said chambers, said upstream chamber communicating with said pressure chamber in said fuel speed metering unit, said downstream chamber communicating with said engine and with a metered fuel pressure chamber in said speed metering unit separated from said fuel supply pressure chamber by a flexible diaphragm, a fuel metering member carried by said flexible diaphragm and shiftable with respect to said return liow metering orifice to regulate the flow of return fuel therethrough, and thermostatically operated means operatively connected to said fuel metering member and to said exhaust manifold and responsive to changes in temperature of the gases Within said manifold to shift said fuel metering unit with respect to said return iiow metering orifice, said thermostatically operated means having a chamber communicating with the atmosphere through a conduit passed through said exhaust manifold, temperature responsive means in said chamber operatively associated with said metering member and adapted to exert a force on said metering member proportional to exhaust manifold temperature, and pressure responsive means in said chamber communicating with said intake manifold and abutting a portion of said temperature responsive means to maintain said temperature responsive means in a taut condition.

3. ln a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, fuel speed metering means connected to said fuel supply and adapted to communicate with said engine intake manifold to supply fuel thereto, said metering means having a speed governor, a fuel metering orice and a shiftable fuel metering member connected to said governor for adjusting the size of said orifice in accordance with engine speed, a load metering unit connected in series with said fuel supply and said fuel speed metering means and thermostatically operated means operatively connected to said shiftable fuel metering member and to said exhaust manifold and responsive to changes in the temperature of the gases within said manifold to shift said fuel metering member with respect to said fuel metering orifice.

4. In a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, a fuel metering unit connected to said fuel supply and adapted to communicate with said engine intake manifold to supply fuel thereto, said metering unit comprising a fuel metering orifice and a shiftable fuel metering member shiftable with respect to said orifice to vary the flow of fuel therethrough in accordance with engine requirements, thermostatically operated means operatively associated with said shiftable fuel metering member and responsive to changes in temperature of the gases Within said exhaust manifold to shift said fuel metering member with respect to said orifice, said means having a bimetallic thermostatic coil ycommunicating with said exhaust manifold through a conduit passed through said manifold and vented to the atmosphere, said coil being operatively linked to said metering member to shift it with respect to said orifice in response to exhaust manifold temperature changes, and means associated with said coil for continuously maintaining said coil in a taut condition.

5. ln a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, fuel speed metering means connected to said fuel supply and adapted to communicate with said engine intake manifold to supply fuel thereto, said metering means having a speed orifice and a shiftable fuel metering member connected to sm'd governor for adjusting the size of said oriiice in accordance with engine speed, a load metering unit connected in series with said fuel supply and said fuel speed metering'means, thermostatically operated means operatively connected to said shiftable fuel metering member and to said exhaust manifold and responsive to changes in the temperature of the gases Within said manifold to shift said fuel metering member with respect to said fuel metering orifice, and pressure responsive accelerator fuel boost means communicating with said intake manifold and operatively connted to said shiftable fuel metering member and said thermostatically operated means to oppose the response to low temperature exhaust gas of said thermostatically operated means at high vacuum intake manifold conditions and to exert a fuel boosting force on said shiftable fuel metering member in response to high pressure intake manifold conditions.

6. ln a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, fuel speed metering means connected to said fuel supply and adapted to communicate with said engine intake manifold to supply fuel thereto, said metering means having a speed governor, a fuel metering orifice and a shiftable fuel metering member connected to said governor for adjusting the size of said orifice in accordance With engine speed, a load metering unit connected in series with said fuel supply and said fuel speed metering means, thermostatically operated means operatively connected to said shiftable fuel metering member and to said exhaust manifold and responsive to changes in the temperature of the gases Within said manifold to shift said fuel metering member with respect to said fuel metering orifice, and pressure responsive accelerator fuel boost means communicating with said intake manifold and operatively connected to said shiftable fuel metering member and said thermostatically operated means to oppose the response to low temperature exhaust gas of said thermostatically operated means at high vacuum intake manifold conditions and to exert a fuel boosting force on said shiftable fuel metering member in response to high pressure intake manifold conditions, said accelerator fuel boost means having fluid bypass means thereon to limit the boosting force developed thereby.

7. In a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, fuel metering means connected to said fuel supply and adapted to be connected to said engine to regulate the flow of fuel thereto according to engine speed, thermostatically operated means operatively connected to said fuel metering means md communicating with said exhaust manifold and responsive to changes in temperature of the gases Within said manifold to provide a boosting force to said fuel metering means to supply additional fuel to the engine under cold starting and Warm up conditions, and solenoid operated means connected to said thermostatically operated means for increasing the boosting force thereof during cold cranking of said engine.

governor, a fuel meteringy 8. In a fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, a fuel metering unit connected to said fuel statically operated means loperatively connected to said fuel metering member and to said exhaust manifold and responsive to changes in Vtemperature of the gases Within Y said manifold to provide a boosting force to said fuel lmetering unit to supply additional fuel to the engine under cold starting and warm up conditions, and solenoid operated means connected to said thermostatically operated means for increasing the boosting force thereof during cold starting of said engine.

9. In a 'fuel metering system for an internal combustion engine having an intake and an exhaust manifold, a fuel supply, a fuel metering unit connected to said fuel supply and adapted to be connected to said engine to regulate the flow of fuel thereto according to engine air consumption, said metering unit comprising a fuel metering orifice and a fuel metering member shiftable With respect to said orifice to vary the iiow of fuel therethrough in 4accord-ance with said engine air consumption, thermostatically operated means operatively connected to said fuel metering member and to said exhaust manifold and responsive to changes in temperature of the gases Within said manifold to provide a boosting force to said fuel metering unit to supply additional fuel to the engine under cold start-ing and Warm up conditions, solenoid operated means connected to said thermostatically operated means for increasing the boosting force thereof during cold starting of said engine, and said solenoid operated means comprising a solenoid coil and an armature, said armature abutting a portion of said thermostatically operated means to provide a force thereto in response to cranking of said engine.

10. A fuel injection system for an internal combustion engine comprising a fuel supply, a fuel speed metering unit having a pressure chamber communicating with said fuel supply through a fuel feed conduit and also communicating with said fuel supply through a return flow metering orifice in said fuel supply pressure chamber, a fuel load metering unit having an upstream chamber and a downstream chamber and a load metering orifice Vconnecting said chambers, said upsteam chamber communicating with said pressure chamber in said fuel speed supply and adapted to be connected to said engine toV in accordance with said engine air consumption, thermometering unit, said downstream chamber communicating with said engine and with a metered fuel pressure chamber in said speed metering unit separated from said fue] supply pressure chamber by a ilexible diaphragm, a fuel metering member carried by said ilexible diaphragm and shifta'ble'with respect to said return ilow metering orifice to regulate the iiow of ret-urn fuel therethrough, thermostatically operated means operatively connected to said fuel metering member and to said exhaust manifold and responsive to changes in temperature of the gases Within said manifold to shift said fuel metering unit with respect to said return iiow metering orifice, said thermostatically operated means having a chamber communicating with the atmosphere through a conduit passed through said exhaust manifold, temperature responsive means in said chamber operatively associated Wit-h said metering member and adapted to exert a boosting force on said metering member proportional to exhaust manifold temperature, and solenoid operated means connected to said temperature responsive means and electrically connected in the engine starting circuit for increasing said boo-sting force during cold starting of said engine.

ll. In a fuel metering system for aninternal combustion engine Vhaving an intake and an exhaust mani-fold, a fuel supply system, return flow fuel metering means in said supply system, speed responsive means operatively connected with said metering means and adapted to be connected to said engine to regulate the flow of fuel thereto according to eng-ine speed, said return liow metering means comprising a fuel metering orifice and a fuel metering member shift-able With respect to said orifice, pressure responsive means adapted for connection to the engine air intake system and operably connected to said member to vary the flow of fuel to said engine in accordancewith said engine air consumption, and thermostatically operated means operatively connected to said fuel metering member and to said exhaust manifold and responsive to changes in temperature of the gases Within said manifold to adjust said fuel metering member to restrict the return ofw and thereby supply additional fuel to the engine under ycold starting and Warm up conditions.

References Cited in the le of this patent UNITED STATES PATENTS 2,84l,129 Reggio July 1, 1958 2,847,983 Dietrich Aug. 19, 1958 2,852,011 Pringham Sept. 16, 1958 2,876,758 Armstrong Mar. 10. 1959 

